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Posts Tagged ‘time window in stemi’

We know primary PCI is a race against time  both for the  patient  and his  physician.

What is the upper limit for this unique race where the stakes  are high   and it involves  human lives  and  big  corporate  warfares  ?

  1. 6 hours
  2. 12 hours
  3. 24 hours
  4. 36 hours
  5. 54 hours
  6. Time does not matter . You can do a PCI as late as possible as long as  patient has sufficient insurance coverage and we have the expertise

Answer :

Please note there is  only one exception  . Cardiogenic  shock has been given a extended  lease of time window (Which can be technically up to  54 hours ) . PCI can be performed   if the onset of shock  is   within 36 hours  of STEMI  and to be performed within  18 hours after the onset ! )

* Even though we  have a  well set criteria for re-perfusion which bans primary PCI to be performed after 12 hours , cardiologists have enough technicalities to overcome this hurdle and keep doing the futile pPCI well after 12hours.

How they are   able to indulge in these futilities   without  any ethical issue ?

The answer  is very simple. Instead of calling it as primary PCI they refer to it as delayed PCI or rescue PCI !  Strict time specific guidelines are only for primary PCI . By changing the terminologies they   make a mockery of the concept of time window which  is vital for any intervention for STEMI !

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A patient with  chest pain   is being rushed   into the ER  of  a medium sized cardiac facility in an urban county of India .The fellow briefs the senior consultant cardiologist about the arrival of  this  extensive anterior  STEMI  over phone.  The  consultant  enquires  about the “symptom to door time” and  was little concerned  when the fellow said ” it is only  2 hours sir”  .The fellow was amused with the consultant’s  reaction.

The consultant arrived in 15 minutes  and  began  the all important  discussion with the  patient  and his spouse  .(Meanwhile tablet clopidogrel and Aspirin was  loaded  per orally . Note : Heparin is not given yet )

Cardiologist : It is a  massive heart attack . One of your coronary artery  got  blocked suddenly , I have to remove the block at the earliest . There are  two ways of doing it .  One is fibrinolysis which lyses the clot .It can open up  your vessel  , though incompletely but would prevent myocardial damage  at the earliest .

The other one is PCI ,  which if performed rapidly  will completely  open up the vessel in question , what  we call TIMI 3 flow ,  But it has to be done within one hour.

Patient : Which is better doctor for me ?

Cardiologist : My cath lab  logistics  does not allow me to do a  PCI within the stipulated  time ,   still  I wish  to perform   a primary angioplasty  as i am not a believer  in thrombolysis !

So , even though you are  eligible for both modes of re- perfusion, in the strict sense doing a  PCI  which will  ultimately be  delayed  beyond the recommended time window  is technically contraindicated “

(Please  be notified : Currently , if the delay is during the procedure due to some technical issues after starting the procedure  or if the delay is at  the patient   level in arranging the required finance or insurance clearance it can be condoned without any ethical issues )

Patients spouse : Doctor please save my  husband . You  start  the fibrinolysis  every minute is risky isn’t doctor , and do the PCI once its ready doctor .

No . . . Fibrinolysis  does not combine well with PCI  in fact it will worsen the situation .   Thats what FINNESSE  study says . We can do only one of them . . . not both .

The patient and spouse (Terribly confused  by now )

Cardiologist:  By the way , what is  your insurance limit  sir ?

Patients spouse : Its 4 lakhs

Cardiologist : OK , that should be suffice  90 out of 100 times . Any way keep another lakh ready in case I need IABP.

Patient : My pain is worsening doctor at least relieve  my pain till this debate  is over !

(A patient’s relative  browses his  i phone  and argues  the  cardiologist   to administer streptokinase at the earliest . Suddenly  the patient family lobbies for fibrinolytic mode  empowered by the i phone guy )

One of them shouts “Please doctor you do something either take him inside cath lab or  start a fibrinolyitc therapy ”

How did the cardiologist  fight his way through ? ( He gulps a cup of coffee and  starts a fresh discussion)


Cardiologist : 
I am sorry , you have come too early  for PCI .  Guidelines do not allow me to choose PCI in the first hour  as our  anticipated delay for PCI is more than 3 hours . I wish you arrived after  the 3 hour window .

“Of course you are on time for thrombolysis”  which  unfortunately I am against !

Now, I am going to wait ( You may think it is a waste of time i call it as patient preparation time )  .This waiting period incidentally  allows us to cross  three  hour  time  window ,  then the issue of not lysing  does n’t creep in at all . A PCI done after 3 hours is not a race against time , while a PCI done early is like  a power play in cricket .

I do not know whether this delay which is happening  right now –  Intentional /Unintentional,  Scientific / unscientific reasons  would  damage your heart or not !

Since you have an extensive MI , I earnestly believe  with all my wisdom and knowledge, you will do well with primary PCI  even if  i do it  little late .  Please allow me to violate the standard criteria in the interest of your heart .

Cardiologist : I wonder , if you had arrived little late we wouldn’t be discussing this terrible conversation at all .Your myocardium  will also feel thrilled for getting a better mode of re-perfusion. You put me in an awkward situation by coming early !

Patient : But  . . . doctor every one  tells me ,  one should reach the hospital  after a heart attack  at the earliest  is it not ?   Please believe me doctor ,  I  made  extraordinary  efforts to  arrive early to your hospital , but you have put me on hold doctor !

Cardiologist :I agree  . . . but you won’t understand the modern jargons  in  interventional  cardiology ,  some times (Or is  it many times !) we will be doing the diagonally opposite to what  is   preached  in text books  .  Both intentional and unintentional delays are common  in the emergency cardiac  care . Do not bother about it   . . . science will take care of it !

Patient : You mean  . . . you are going to waste the golden hour in STEMI by simply arranging for cath lab staffs and machinery .

Cardiologist : You got the point right ! Just sit back enjoy the  flight !

Patient : Your wish is my wish doctor . Please handle with care doc !

* Please note this is an imaginary conversation ( Most often happens in silent mode !) in many of the cath labs which do not have 24 hour service. In a country  with  100 crore population like India ,  less than a dozen cathlabs  work round the clock . Guess  how often such a  situation would come in day to  day cardiology practice.



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Time is muscle .This  may sound as  an old fashioned statement now ,  for many of us. But the fact remains. Every minute following  STEMI ,  myocytes  keep  losing it’s life one by one unless , the  intervened.

The prevention of myocyte death can be accomplished by three ways

  1. By early thrombolysis
  2. By Primary angioplasty
  3. The  one  that happens naturally by a process called spontaneous thrombolysis *

* Most have a  strong belief  that the  natural forces are incompetent to lyse a  small thrombus within our coronary  arteries  ( While  , we  fully  realise   natural  forces  like  the Tsunami can wash out  the entire ocean floors  ) . Never under- estimate the force of  nature !

Balloons are not privileged !

 

It is widely accepted , a time window of up to 12 hours is optimal for reperfusion. Beyond that time , there is no point in reperfusing  the muscle  as   it  might have died. While ,  the majority of cardiologists agree  to this and they  promptly  refuse  to thrombolyse ,   if the patient comes  12 hours after an onset of STEMI  .They are labeled  ” late on  arrival”  and  coded  as ineligible for thrombolysis.

The moment they are labeled as ineligible for lysis , a dangerous thought process runs across  the minds of  many cardiologists. It is  possibly  the most important paradox (Shall  we call it as sense failure ? )

Such lysis ineligible  patients    become  automatically eligible for primary PCI . . . It is curious  to note , the  time window for primary PCI is also less than 12 hours is strangely forgotten.

It has become a prevalent  practice  by all unscientific means  , most  cardiologists extend  the time window for primary PCI well beyond 12 hours  , some even up to 36-48 hours.  No wonder . . . then why open artery trial (OAT) miserably failed . Even a  novice  can predict the out come when  one tries  to resuscitate the  dead muscle .

Final message

Myocardium  does not behave in a privileged  manner  during a STEMI.  It  simply does  not bother  about the way  by which  it is going to be rescued and reperfused  .All it needs   is a timely help. It can not extend its   life just because it is being rescued by a  sophisticated modalities like pPCI.

If the patient is late for thrombolysis ,  he is late for  primary PCI as well .

Please do not change the time window in STEMI  according to  our  whims and fancies . It is  an  unscientific and unprofessional  way to practice cardiology .

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Acute MI is a major medical emergency encountered in ER . Prompt adminstration of thrombolytic agents or rapid   triaging for a  primary PCI   may be required . The whole concept of management of STEMI  revolves around time as a therapeutic   target .Every minute counts . The beneficial effects of  reperfusion   and the resultant  myocardial salvage  rapidly declines over time . Hence ,  the symptom to door time  remains the ultimate determinant of  outcome in most situations.

So , estimating the  time window of  “Symptom to door time ” becomes an all important parameter. This is often done by paramedics .

The apparently  simple  job  measurement of time window  can be  misleading at times especially in elderly, diabetic and alcohol abusers .

When  a patient  says he has chest pain since yesterday straightaway he is excluded from reperfusion strategies as 12 hours  would have elapsed

When a patient  describes  chest  pain since two days , but  more intense  only since today morning what does it imply ?

  • The first episode of pain could  either  preinfarction angina or infarct
  • The second episode of pain could again be the continuation of same  angina or conversion of that angina into infarct

So ,  calculating the time window  when a  patient has recurrent episodes of angina prior to an MI is a real difficult issue.For the benefit of doubt, we have to take the last episode of chest pain  which was continuous and more severe as the infarct pain.

How does ECG help to time STEMI ?

When it is difficult  , to differentiate pre infarction angina from infarct pain, the ECG may give  useful clues to time the STEMI.

  • Degree  ST elevation
  • T wave inversion
  • Q waves

Among the  above three ,T wave inversion is most useful to time an infarct. If T wave begins to invert, it can generally assumed the acute  infarct process is  almost complete . Q waves are less reliable  to time a acute MI as ischemic stunning can in the  very early phase of STEMI   inscribe a q wave over the infarct territory.

How will you time a STEMI in silent MI ?

There is no symptom to door time in patients with silent MI . Many do not even reach the door , for the simple reason there is no symptom that drives them to hospital. Those who are refered  have vague non cardiac symptoms and incidental ECG  which shows STEMI like changes. Here , the decision to thrombolyse is taken entirely on the basis of ECG *finding .

Note : Cardiac enzymes are can also be  used  to  diagnose  to estimate the time window .

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